Diagnosis
The Rowenta VU5670 Turbo Silence Stand Fan utilizes a digital timer circuit that controls a power relay. When the timer fails to shut off the fan, the issue is typically a "logic hang" in the control board or a failure of the mechanical relay to trip. In a logic hang, the internal countdown clock continues to run in the background, but the signal to open the circuit (cut the power) never reaches the relay. This is often caused by a voltage spike or a residual charge in the capacitors that prevents the microcontroller from resetting its state. To confirm this is a logic error rather than a mechanical failure, set the timer for the minimum increment (usually 30 minutes). If the fan continues to run past that window without any clicking sound coming from the base, the relay is not being triggered. If you hear a distinct "click" but the blades keep spinning, the relay contacts have likely welded shut, meaning the physical switch is stuck in the "on" position regardless of the timer's command.
How to Fix It
Since the VU5670 does not have a dedicated "Reset" button, you must perform a hard power cycle to flush the volatile memory of the control board.
- Turn the fan off using the power button on the control panel.
- Physically disconnect the power cord from the wall outlet. Do not simply turn off the power strip or wall switch.
- Wait exactly 5 minutes. This duration is critical to allow the capacitors on the PCB (Printed Circuit Board) to fully discharge, which clears the corrupted timer state.
- While the unit is unplugged, press and hold the power button for 10 seconds to bleed off any remaining residual energy.
- Plug the unit back into a direct wall outlet, avoiding extension cords or surge protectors for this test to ensure consistent voltage.
- Power the fan on and set the timer to the shortest possible duration (30 minutes).
- Observe the timer display; if the countdown progresses and the unit shuts down at zero, the logic glitch has been resolved.
If That Didn't Work
- Inspect for Control Panel Moisture: If the fan is used in a humid environment, condensation can build up behind the membrane buttons. Use a can of compressed air to blow out the gaps around the timer buttons. Debris or moisture in the tactile switches can send "phantom" signals to the board, effectively resetting the timer or overriding the shut-off command.
- Check for Voltage Fluctuations: If the fan is plugged into a heavily loaded power strip, "brownouts" or voltage drops can cause the digital timer to freeze while the motor continues to spin. Move the VU5670 to a dedicated 120V/230V wall socket to see if stable current restores timer functionality.
- Relay Contact Cleaning: If you are comfortable opening the base (and the unit is out of warranty), locate the rectangular black relay on the PCB. Use a plastic probe to gently tap the top of the relay while the timer is supposed to be triggering. If the fan shuts off upon impact, the relay is mechanically sticking and needs to be replaced (Part # varies by region, but it is a standard 12V/250V DC coil relay).
- Firmware Loop Reset: Try setting the timer to the maximum setting (typically 8 hours) and then immediately reducing it back down to 30 minutes. This sometimes forces the microcontroller to re-index the timer sequence and can break a software loop.
Heads Up
- Avoid using the timer function in conjunction with high-wattage space heaters on the same circuit, as the electromagnetic interference (EMI) can disrupt the VU5670's sensitive timer logic.
- Always ensure the fan base is on a completely level surface; extreme tilts can occasionally cause the internal relay to vibrate or fail to seat properly.
- Clean the motor housing with compressed air every six months; overheating in the motor can lead to erratic behavior in the control board due to heat soak.
- Never use a "smart plug" to override the fan's internal timer, as the sudden power cut can sometimes corrupt the VU5670's internal memory settings.